I remember seeing part of it a few years ago, and it just bugs me how I don't remember what it was called.

Here's some things I remember about it.
-There was a scene in one episode where some guys were in a desert and they had to keep warm, and I think there was mentions of drinking their own piss

-An episode where the main character and a bad guy were in a swampy area I think

-It was a serious anime/adult. The atmosphere always seemed kind of dark. Rainy. Gloomy.

-The characters were drawn a bit more realistically, not with big eyes and small noses

-The main character was an adult male and he was a good guy I think. Not really a cop, but something similar.

-The title of the anime MAY have had the MCs name or occupation, but I'm not too sure.

-It wasn't anything too recent